1. Field of the Invention
This invention relates generally to eyewear to be used as a reading aid for dyslexia patients, and particularly to apparatus for fulfilling everyday reading requirements of persons afflicted with this perceptual problem.
2. Description of the Background Art
A great deal of conjecture exists regarding the causes of dyslexia, primarily as observed in young adults and school-age children. Older views, which relate the cause of primary dyslexia to a dysfunction of the cortex, have not been adequately borne out in either statistical studies nor postmortem studies. A foremost authority in the country, Harold Levinson, M.D. of Greatneck, N.Y., points out in two significant patents issued to him and his colleagues, U.S. Pat. No. 3,842,822 and U.S. Pat. No. 3,906,644, that significant medical discoveries underlying their inventions indicate there exists in dysmetric dyslexic children, a sub-clinical nystagmus, or eye vibration. The vibration is at an almost imperceptible frequency or number of beats per second, as demonstrated by electronystagmographic recordings taken when the eyes were closed, to eliminate fixation. It is the Levinson proposition that children suffering from the condition indicated are unable to properly fix vision because of the rhythmic, uncontrollable eye movement. It is further noted that the eye movement is sub-clinical in nature, in that measurement of it requires an electronystagmographic frequency recording under favorable conditions. In Levinson '822, a reading or symbol-recognition test, capable of being administered to a large examination group of children, produced blurred vision only in those of the group who possibly suffer dysmetric dyslexia. The test induces an eye oscillation of a selected extent which is normally below the level that produces blurred vision in those not affected with dysmetric dyslexia. It is used as an effective diagnostic screening procedure, even for pre-school children with cerebellar-vestibular dysfunctions, and who have not as yet had the opportunity to exhibit poor or refractory response to reading instruction. What is hypothesized by Levinson in '822 is that by inducing an eye oscillation of a selected extent and which is normally below the threshold level producing blurred vision in a normal person, in additive relation to a sub-clinical eye oscillation produces an additive effect and exceeds the threshold level, automatically identifying those who experienced a blurred vision as possibly disposed to dysmetric dyslexia. Thus, in this particular apparatus, Levinson creates an environment which exceeds the compensatory ability of the dyslexic patient and thus identifies those possibly having the syndrome. It can be seen that the producing of blurred vision is non-therapeutic in nature, being merely diagnostic.
Levinson '644, relying on that inventor-author's previously held hypothesis, regarding dysmetric dyslexia, teaches a method which calls for the presentation of reading material in letter or word-size units, one at a time and in reading sequence at a fixed location, so that the child reading is not required to sequentially scan the reading material. The inventor points out that the material is presented in temporal rather than spatial sequence or relation. Thus, there is exhibited only slight or minimal eye vibration which results in minimal ocular overshooting and undershooting and avoids blurring and scrambling, the most common symptoms of the dyslexia affliction. Levinson further teaches that the technique of '644 makes use of a heretofore unknown compensatory mechanism existing in dysmetric dyslexic children, namely a functional narrowing of the visual field so as to avoid blurring. The instant inventors point out at this time that what Levinson observed in his last series of experiments, leading to '644, is the very phenomenon which they have sought to capitalize upon with the instant invention. The significant difference is, however, that the instant invention purposefully narrows the visual field so as to aid the dyslexic patient in making the aforementioned compensation and thus, amelliorates eye oscillation.
In 1983, Nelson was issued U.S. Pat. No. 4,379,699, a significant number of years after Levinson patented his method of presenting reading material to dysmetric dyslexic-identified children. Nelson teaches a method and apparatus for improving the reading efficiency of persons with specific dyslexia. Unlike Levinson, Nelson does not go into the specific categorization of dyslexia types, but rather appears to be dealing with what he terms "specific dyslexia" and what appears to be similar to the malady described by Levinson as dysmetric dyslexia. Irrespective of the nomenclature employed, the method and apparatus of Nelson appears therapeutic in that the objective is to provide a means whereby the dyslexic patient might improve reading efficiency, the most notable deficiency of these dyslexia-afflicted persons. The Nelson method of effecting an improvement in reading efficiency includes providing to the dyslexic student reading material wherein the matter has a brightness substantially greater than that of the background on which the reading matter is provided. Here, unlike the Levinson apparatus, substantial change is made to the quality or at least the physical attributes and characteristics of the material being read. Like the Levinson devices, however, the Nelson device also requires some form of preconditioning performed on the reading material and thus, is extremely limited for usage by those dyslexic patients who, in spite of their malady, are quite capable readers and would perhaps be expert were it not for the fact that there is very little way, short of drug therapy, for them to control the oscillatory eye movements that are the hallmark of the dyslexia affliction.
One of the instant inventors was first diagnosed as dysmetric dyslexic at age 26 by Harold Levinson, M.D., the patentee of Levinson '822 and '644. Throughout childhood, and to young adulthood, she had overcome a great number of difficulties and acquired consummate reading skill. Nevertheless, the dyslexia dysfunction was never more pronounced or severe as when she entered the university and attempted courses such as the calculus which utilized atypical symbology. After diagnosis by Levinson, and initiation of a mild drug therapy, greater concentration was achieved and was a considerable help in reading through the vast amounts of scientific material. Some diminishment of the reading problem was noted but, most notable was the ability to maintain balance that could be attributed to nothing other than the effect of anti-vertigo medications. Then, quite serendipitously, she acquired bifocals, where she had formerly used a set of reading glasses of mild prescription and alternately distance glasses of a very strong prescription. When first reading ordinary materials with the new bifocals, the dyslexic inventor found that she was reading with a true narrowness of vision in that she was able to observe clearly only a few alphanumeric characters at a time, all remaining characters in the line, both before and after the target phonetics, being blurred by the peripheral far-vision correction. It was at this point also that she began to truly appreciate the Levinson observation of oscillatory eye movement. The instant inventors are thoroughly convinced that this is indeed the problem faced by dyslexic patients. It is relegated to eye oscillations of a horizontal nature and not in much, if any, respect above or below the line being read. When this and similar reading phenomena were explained to the second inventor of the instant invention, they decided to construct a device that would comprise a non-drug, but therapeutic, protocol to aid the dyslexia victim. After a careful and diligent examination of the prior art, the instant inventors decided that, helpful though they may be, the actual apparatus of Levinson and Nelson could not be configured so as to aid any and all dyslexics in any reading situation.
It is therefore a primary object of this invention to provide a dyslexic reader with a simple apparatus that may be used in any reading situation and would aid the reader in acquiring the narrow (compensatory) vision necessary to defeat the constant fore and aft eye oscillatory motions as the reading material is scanned.